In the production of polyurethane foams, a polyol is reacted with a polyisocyanate in the presence of a polyurethane catalyst and a blowing agent. Unfortunately, certain blowing agents, namely chlorofluorocarbons (so-called "CFCs"), are hazardous to the environment, specifically the ozone layer of the atmosphere. Hence, alternatives to the use of CFC's are being actively sought by the polyurethanes community.
The use of a portable foaming apparatus employing a foam forming formulation to provide on-site generation of polyurethane foam is well-known in the art. By way of illustration, U.S. Pat. No. 3,882,052 discloses the use of such an apparatus to provide non-froth polyurethane foam. For other applications, frothed foam is suitably produced using the portable foaming apparatus by incorporating into the foam forming formulation an auxiliary CFC blowing agent, such as dichloro-difouoromethane, commercially available as FREON 12, a product of DuPont Company. When injected into the foam forming mixture, the auxiliary blowing agent serves to augment the function of the static mixer in bringing about thorough blending of the foam forming ingredients. Since the auxiliary CFC blowing agent is hazardous to the environment, alternatives to the use of CFCs in the production of frothed foam would be highly desired by frothed foams manufacturers.
Co-pending U.S. application Ser. No. 07/693,162 discloses a process for producing, by means of a portable foaming apparatus having a static mixer, a polyurethane foam by reacting a reaction mixture comprised of a polyol, an organic isocyanate, a foaming/frothing agent, and a reaction catalyst, the improvement comprising employing monochlorodifluoromethane (which is a so-called "soft chlorofluorocarbon" or "HCFC") as the sole blowing/frothing agent in said reaction in order to produce a CFC-free essentially closed-cell rigid or semi-rigid polyurethane foam. Although the process of this co-pending patent application is expected to provide a significant advantage in the production of foams from an environmental standpoint, as compared to the production of CFC blown/frothed foams, it has now been found that the stability during storage of foam formulations containing the monochlorodifluoromethane blowing/frothing agent is not as great as might be desired. Accordingly, new foam formulations containing monochlorodifluoromethane, but which are stable against degradation during shipping and storage, and prior to use, would be highly desired by the polyurethane foam formulation community. Heretofore, suitable formulations have not been known based upon the knowledge of the present inventors.